Tappet



Au@ 19, 1947. w. D. coRLE-r" .2,426,083

TAPPET Filed sept. 9, 1944 Patented Aug. 19, 1947 TAPPETl vWebster D. Coriett,

Oak Park, Ill., assignor to Standard Screw Company, Hartford, Conn., a corporation of New Jersey Application september 9, 1944, serial No. 553,329

(o1. 12a-9o) 1 Claim.

This invention relates to a tappet. One common use for tappets is in connection with the operation of valves in which the tappet is positioned between a cam and a valve operating means, and one use. of the structure ofthe present invention is, therefore, that of a valve tappet.

One object of the invention is to provide a valve tappet which will operate satisfactorily.

Another object of the invention is to means for securing tension or setting up tension in a portion of the screw which is positioned in the tappet. v

Other objects will appear from time to time throughout the specification and claim.

The invention is illustrated more or less \diagrammatically in the accompanying drawings, wherein:

Figure 1 is a longitudinal section with parts broken away and parts in elevation, showing one form of the device, with a diagrammatic showing of a heating means for use in its manufacture;

Figure 2 is a similar view illustrating a modified form of the device; and

Figure 3 is a similar view illustrating a still further modification.

Like parts are indicated by like characters throughout the specication and the drawings.

In the form shown. in Figure 1 the tappet includes a hollow body I having a mushroom head` 2 formed integrally therewith. The outer surface of the head may be rounded,

as at 4, adjacent the head.

A portion of the barrel or body of the tappet is pressed or formed inwardly by shaping the groove 5, which may serve as an oil groove. This may be rolled in the barrel and when it is formed the wall is forced inwardly and this portion is threaded, as at 6. Adjacent its open end th'e tappet barrel may be somewhat reduced, as at 1. A perforated and interiorly threaded plug 8, which may have an exterior shoulder 9, is seated in the open end of the barrel and preferably in the reduced portion 1. The threaded plug is permanentlylocated in place and may be hydrogen welded or otherwise permanently secured. The threads in the portions 6 and 8 are preferably formed after the plug 8 has been secured in place, and the threads are thus cut continuously through both portions.

With the tappet thus far completed-that is to say, with the formation of the two threaded portions-a screw not shown may be inserted in the threaded portion of the plug 8 and that portion of the tappet barrel whichlies between the groove provide Y 5 and the reduced portion 1 is heated and a pull which is engaged in the is exerted on the screw threaded portion 8, and this results in a. permanent stretch in. that portion which has been heated. Since the threads in the portions -6 and 8 were formed originally in a continuous opera.- tion, and therefore are formed along a continuous pitch, the stretching just mentioned results in making the two threaded portions slightly ofi as at 3, and the -body of the tappet may be reduced somewhat,

pitch with respect to each other.

When now the permanent threaded screw is inserted and engages the threads in the portions 6 and 8, the shank of this screw becomessomewhat stretched between the two threaded portions and a locking effect results. In the form shown in Figure 1, the screw comprises a relafl tively short threaded portion I0, the threads of which are Vin mesh with the threads of the portion 5, and a relatively longer threaded portion Il, the threads of which are in mesh with the threaded portion 8. The two threaded portions I0 and I I may be separated by a reduced portion I2l Where this is the case the stretching of the screw will occur primarily in the reduced portion l2. The screw is provided with a head I3 which is preferably of angular cross section and' may have an outer rounded face I4.

While many different methods of heating that portion of. the tappet barrel which is to be lstretched may beused, one convenient and inexpensive method is to surround the portion to be stretched, which is marked with a high frequency heating element y. This element is shown only diagrammatically because such high frequency heating elements arevwell known in the art' and are available at present on the market. The particular details of the high frequency heating element form no essential part of the invention and they are only illustrated diagrammatically.

In the modied form of Figure 2 the tappet parts are the same as those shown and described in connection with Figure 1, with one exception. To provide the necessary stretching of the tappet second groove l5 may be rolled or otherwise formed in the barrel I, and this groove, which will result in an inward enlargement I6, has the eiect of slightly increasing the length of the tappet. When present, the second groove I5 may also'serve as an oil groove, and in this manner the desired result is produced.

The modified form of Figure 3 is the same as 3 4 that shown in Figure 1, except that instead of the hydrogen welding, and this may be done at the screw formed of the two threaded sections I and same time that the insert 8 is welded in place. II and separated by a reduced portion I2, the This form of the invention is shown in Figure 3. screw and its threads are continuous throughout. Whether or not this threaded portion is formed A continuous screw might also be used in the 5 by an insert I'Iv or by inwardly depressingA the modified form of Figure 2. While a continuous Walls of the tube is a matter primarily of conscrew is within the contemplation of the invenvenience in manufacture. Whichever'method tion and may be used instead of the interrupted is used, the parts 6 and 8 or I'I and 8 are norscrew with the tappet bodies of Figures 1 and 2, mally tapped continuously, and then by the heatit is ordinarily preferable to use an interrupted lo ing member Y or otherwise, the barrel of the screw because the reduced diameter facilitates tappet iS arranged So that it can be somewhat the stretch in the screw. Whatever the shape of elongated. Such a construction could be used the screw, some stretch will occurin it, and this with the continuous screw 'of Figure 3 or the gives a spring tension to the screw which is interrupted screw of Figure 1. always, of course, below the elastic limit of the The method of forming the device comprises screw, but which at the same time has the necesgenerally the following steps: sary locking effect. First the tappet is formed and a groove is then Whatever the particular form of the tappet rolled in the body. A threaded insert is welded body and whatever the particular form of the in the open end. The inwardly displaced portion screw, there will be two threaded sections or of the tappet body which has resulted from the portions fixed within the tappet, and these porformation of the groove and the insert are then tions. whether formed originally continuously or threaded, preferably as a continuous operation. not, will have been moved slightly out of pitch Thereafter the body is stretched by any means with respect to each other, either by heating, or process, so that the two threaded portions are by forming a second groove or by otherwise A movd slightly off pitch with respect to each lengthening the space between the two threaded other. Finally the threaded screw is inserted portions. The result of this is that when the for the desired distance and it meshes with the tappetscrew is screwed into position the screw two threaded portions. When this occurs the is somewhat stretched as it engages both threaded screw is somewhat stretched and is thus locked in portions of the tappet and a locking effect is proper adjusted position. exerted on the screw. The device and the method The method for elongating the tappet body producing it have many 'advantages between the two threaded portions may be me- In the first place, the construction is relatively chanical alone; it may include the use of heat or cheap, because among'other reasons, the threaded 35 may include heating and mechanical action in insert 8 may be put in place and a large number combination.

of the tappets may be welded at the same time, The general purpose of thevtappet and of the thus avoiding individual welding of individual method of forming it iS t0 Produce a Self-locking tappets. The threaded insert is thus permatappet and adjusting SCreW assembly. In the nently fixed in the tappet, and in case an emer- 40 Various fOIInS 0f the invention, means are IJIO- gency repair requires the removal of the screw vided which establish tension in the screw II and and the insertion of another screw, any screw Which Create Pressure between the threads in the may be substituted, and it may be held 1n place two threaded sections Il and 8 or in the two by any lock nut of known design The preferred threaded sections 6 and 8, and this pressure locks reduction in the section of the screw-for exthe SCTFW agfiinst turning during OPBYRPOD 0f the ample, at I2-which lies between the two threads 45 motor 1n '.hleh the tappet may be Dosltionei provides elasticity which will keep the torque The lockmg effect may be expresed in terms 0f against turning constant, oven though a Smau definite foot pounds of torque applied to the head amount of wear may be present n the threads in I3 of the screw Il and the amount of this torque the tappet. can be varied by varying the amount of offset or distance by which the thread sections 6 and 8 or I1 and 8 are offset with respect to each other, and therefore in making any given tappet, the distance by which one thread section is moved from the other is determined by the value of the head, which is normally spherical, may be kept concentric with the body of the tappet, and this lkgpect which 1t is desired to establish in is of course important in accuracy and proper I claim,

operation and long life. I

n combination in a tappet, a hollow, generally Although I have shown an operatlve form of cylindrical body, and an integral inward projecmy invention it will be recognized that many tion formed within said hollow body, and an insert changes in the form, shape, and arrangement of positioned in the end of said body and permaparts can be made without departing from the nent] Secured therein away from said projection, spirit of the invention, and my showing is theresaid Snsert and said projection being Screw Another advantage which results from forming 50 the threads generally as a part of a continuous operation is that the axes of the screw, and consequently the bearing surface I4 of the screw fore to b? taken as in a' .sensfa' diagrammatic' threaded, the threads of said projection and of In paftlculfr' the inventon 1S 'not limlted to es said insert being siighuy off pitch with respect to a form 1n which the external groove 5 is present. each other and a screw of Constant pitch engaged For some purposes and in some uses, the presence partly with the threads of Said projection and of such a groove or depression is neither desired partly with the threads of said insert said screw nor necessary, and ina case of that sort, instead provided with a reduced unthreaded portion in of formi-ng the inner projection s by depressmg I0 termediate its ends andbetween the two threaded the Outer Wall 0f the tappet as shown at 5 m portions thereof, said reduced portion being Figures 1 and 2, an insert l1 is put in place dimensioned to corinne the deformation of the within the barrel of the tappet and is welded screw when engaged with the two threaded pob therein or Otherwise permanently Secure@ A tions of the tappet substantially to said reduced convenient Way 0f Securing the .insertll is by 7s portion to thereby presume substantial deformation of the engaged threaded portions of the bolt and tappeti.

WEBSTER D. CORLETT.

REFERENCES CITED The following references are of record in the le of this patent:

Number UNITED STATES PATENTS Name Date Hoern Nov. 7, 1939 Corlett July 9, 1940 coment July 9, 1940 Brackett Sept. '7,v 1943 Luce Feb. 29, 1944 

